Of a Christian Man's Oath

As we confess that vain and rash swearing is forbidden Christian men by our Lord Jesus Christ and James His apostle, so we judge that the Christian religion does not prohibit but that a man may swear when the magistrate requires, in a cause of faith and charity, so it be done according to the prophet's teaching, in justice, judgment, and truth.

But let your Yes be Yes and your No be No. Whatever is more than these is of the evil one.
— Matthew 5:37 (WEB)

Note

Permits judicial oaths (court testimony) while forbidding casual or profane swearing.

Bible references

Matthew 5:33-37 · James 5:12 · Hebrews 6:13-18 · Deuteronomy 6:13 · Jeremiah 4:2